There are a wide variety of hand tools currently available for scoring/etching grooves in construction material. These tools include a variety of hand saws, rasps, utility knives and electrical hot knives for scoring, etching and/or grooving exterior finish insulation systems. The exterior finish insulation system is subsequently coated with cement or mortar.
The exterior finish insulation system is an insulating material generally manufactured from polystyrene (or other similar material, such as Styrofoam®) mounted onto the frame of a building under construction. This exterior insulation provides both insulation as well as a foundation for the exterior finish of the building. After installation, the insulation surface is scored, etched or grooved to accommodate the functional and/or decorative markings required by building code or aesthetic design. For example, decorative grooves, such as geometric designs or trade name indicia, are formed and defined by scoring/etching the insulation.
U.S. Pat. No. 6,905,290 (Casciato) discloses a hand rasp that comprises a planar plate with a removably affixed straight edge guide, and a groove blade that is removably affixed to the posterior surface of the plate. The operator pushes and pulls the rasp in a back-and-forth motion until the desired groove is scored or etched into the construction material. This tool is does not melt EPS foam material and requires the use of a 3-dimensional blade and affixing means attached to the blade.
In order to score, etch or groove the insulation surface, many construction professionals use hand saws or hand rasps. However, each of these presents several disadvantages in terms of waste (of both time and construction material) and dangerous use. For example, hand saws and rasps consist of large blades, making both tools clumsy and dangerous to use at elevated heights. In addition, any minor imprecision in the use of the blade results in irreparable damage to the insulation.
While an electrical hot knife is more advantageous for scoring, etching and/or grooving at elevated heights than either a hand saw or rasp, conventional electrical hot knives present several shortcomings for the construction professional. One typical hot knife tool consists of a sled and two adjustable groove blade holders. The adjustable blade holders are located on one edge of the sled, and can slide freely thereon. Each end of a groove blade is then attached to a respective blade holder, and the latter are then fixed into position before operation. Shapes of groove blades include, for example, square, round or “U”, bevel, angle and “V”.
Before operating the grooving sled, the operator first marks the segment for grooving/etching or scoring by drawing a cutting line on the insulation material. Once the groove blade is attached to the sled, the operator then measures the distance between the straight edge guide of the sled and the blade holder nearest to the straight edge guide. This distance is called the “cutting margin”. Another line, called the “guide line” is then drawn parallel to the cutting line at a distance equal to the cutting margin. Unfortunately, every time a new groove blade is installed onto the sled, the operator will need to measure the new cutting margin; this is due to the fact that both of the blade holders have an adjustable position.
Another drawback of conventional grooving sleds is the requirement of an external straight edge guide along which the sled is guided. The straight edge guide is placed close to the guide line, and the grooving sled slides along the straight edge guide to melt strips of EPS foam board and creates a controlled groove. While performing this procedure, the operator needs to use both hands: one hand to hold the straight edge guide, and the other hand to hold the grooving sled. At the same time, the operator will need to move along the wall to follow the guide. In addition, such an operation occurs at heights, requiring the operator to concentrate on the grooving sled, the straight edge guide, the guideline, and maintaining one's balance.
There is therefore a need for a tool for the grooving, etching or scoring of external insulation material that is both simple and stable to use. Such a device should not require the use of an external straight edge guide; it should allow for quick use when changing groove blades without the need to measure the cutting margin; and should provide for a steady, stable grooving motion when in operation.